ANATOMY OF THE HEART

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Introduction

ANATOMY OF THE HEART � Heart is located in the chest cavity and surrounded in a fluid filled sac called (pericardium) � Walls of the heart are divided into three definable layers. � Epicardium: Is the outer protective layer of the heart wall, it is composed of connective tissues and covered by epithelium � Myocardium: Is the middle layer of the walls of the heart and it is composed of cardiac muscle fibres; It is these fibres that allow heart to contract. � Endocardium: Is the inner layer of the heart walls and it is made up of epithelial and connective tissues. Heart is divided into 2 halves by a septum in the middle, so we have a right half and a left half and each half is further divided into 2 chambers upper one is called atria and lower is known as ventricle. ...read more.

Middle

From the right atrium blood empties into the right ventricle through the atrioventricle valve, Blood flow is in horizontal & forward direction from right atrium to right ventricle, because right ventricle is situated in front as well as to the left of the right atrioventricular opening. Tricuspid valve: Blood flow from the right atrium to right ventricle through the right atrioventricular orifice which is guarded by the tricuspid valve. Right ventricle: Walls of right ventricle are thicker then those of the right atrium and possess muscular ridges called trabeculae carneae. Pulmonary valve: consist of three semilunar cusps, this valve is closed during ventricular relaxation (diastole), preventing backflow of blood from the pulmonary trunk into the right ventricle. ...read more.

Conclusion

It emerge from behind the superior vena cava and runs horizontally to the right. Left pulmonary artery: Shorter and smaller then the right pulmonary artery, it emerge from within the concavity of the aortic arch and runs horizontally to the left. Pulmonary veins: Returns oxygenated blood to the left atrium, usually there are four pulmonary veins two from each lung Aorta: Is the biggest artery in the body that takes oxygenated blood directly from the left ventricle. It divides into ascending and descending aorta and then further divides into different branches Superior vena cava: Formed by the union of the two brachiocephalic veins, it terminates into the right atrium Inferior vena cava: Arise from the level of 5th lumber vertebral vertebra, and bring blood back to right atrium from the lower body. ...read more.

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